The ability of insulin to suppress whole body and regional lipolysis will be evaluated in lean (n=8), lower-body obese (n=8), and upper-body obese (n=8) women. Whole body lipolysis will be evaluated by 2H5-glycerol kinetics and regional lipolysis will be evaluated by placing microdialysis probes in subcutaneous abdominal and femoral adipose tissue. Relative changes in glycerol during insulin infusion will be used to assess inhibition of lipolysis. Intra-abdominal fat mass will be assessed by CT.